Known displaceable-head floodlight units (moving lights or moving heads) employ gas discharge lamps as their intensive light sources and provide a plurality of color and pattern effects implemented by color filters and by stamped out metal stops (so-called gobos) mounted on motor-driven plates and displaceable into the light path. In this manner many color and pattern combinations are feasible.
As regards conventionally used light sources, for instance high intensity discharge lamps of 250 to 1,200 watts, cooling said lamps is mandatory on account of their large heat dissipation. In general a controlled blower system will be required, entailing the drawback that dust and other contaminant particles sucked into the blower airflow quickly shall soil the inside of the floodlight unit, in turn requiring cumbersome cleaning in particular of the optical components.
In general the gas discharge lamps suffer from the drawback of short service life and also reduced output with time, requiring in general premature replacement of such light sources.